Synthesis, Spectral Characterization of Polymeric Nickel(II) Tetrathiocyanato Diargentate(I) Complexes with Some Acylhydrazones and Their Bio-activity

Abstract

Polymeric heterobimetallic complexes of the type Ni[Ag(SCN)₂]₂.L (where L = acetophenone benzoylhydrazone (abh), acetophenone isonicotinoyl hydrazone (ainh), acetophenone salicyloyl hydrazone (ash), acetophenone anthraniloyl hydrazone (aah), p-hydroxy acetophenone benzoylhydrazone (phabh), p-hydroxy acetophenone isonicotinoyl hydrazone (phainh), p-hydroxy acetophenone salicyloyl hydrazone (phash) and p-hydroxy acetophenone anthraniloyl hydrazone (phaah) were synthesized and characterized with the help of elemental analyses, electrical conductance, magnetic moment, electronic and IR spectra, thermal and X-ray diffraction studies. Nickel(II) in the complexes has spin-free octahedral geometry. The hydrazone ligands are bi-coordinate bonding through > C═O and > C═N-groups. The complexes form a polymeric structure by bridging SCN groups between two metal centers. Thermal studies (TGA and DTA) on Ni[Ag(SCN)₂]₂.ash indicate multi-steps decomposition pattern which are both exothermic and endothermic. X-ray powder diffraction parameters for Ni[Ag(SCN)₂]₂.ash and Ni[Ag(SCN)₂]₂.phainh correspond to tetragonal and orthorhombic crystal lattices respectively. The ligands, as well as their complexes, show significant antifungal and antibacterial activity. The metal complexes are more active than the parent ligands.

Keywords:

• Heterobimetallic complexes
• thermal studies: antifungal & antibacterial activity
• acylhydrazones
• electronic and IR spectral studies

Acknowledgments

The authors thank the Director, Institute of Engineering and Technology, C.S.J.M. University Kanpur for providing laboratory facilities, the Head, Chemistry Department, Indian Institute of Technology, Kanpur for recording, I.R., electronic spectra and thermal and X-ray diffraction studies.